[Crash-utility] Re: [PATCH v2] memory: Handle crash failure in linux-next caused by struct kmem_cache changes

Since kernel commit cf338283652f ("slab: remove struct kmem_cache_cpu") in linux-next there is no more 'cpu_slab' member in struct kmem_cache. Pick 'cpu_sheaves' as an alternative kmem_cache member for kernel-next to identify the SLUB case. Without the patch, crash fails to start on kernel-next with the error message: crash: invalid structure member offset: kmem_cache_s_num FILE: memory.c LINE: 9988 FUNCTION: kmem_cache_init() This fix: - allows the crash to start with no errors for kernel-next. - make the 'kmap -s' command working again for kernel-next. - throws an error message on 'kmem -S' command if no 'cpu_slab' member presents in struct kmem_cache: kmem: -S not supported for this kernel Signed-off-by: Mikhail Zaslonko <zaslonko(a)linux.ibm.com&gt; --- memory.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/memory.c b/memory.c index cbc8d2f..17423a5 100644 --- a/memory.c +++ b/memory.c @@ -672,6 +672,7 @@ vm_init(void) } else if (!VALID_STRUCT(kmem_slab_s) && !VALID_STRUCT(slab_s) && !MEMBER_EXISTS("kmem_cache", "cpu_slab") && + !MEMBER_EXISTS("kmem_cache", "cpu_sheaves") && (VALID_STRUCT(slab) || (vt->flags & SLAB_OVERLOAD_PAGE))) { vt->flags |= PERCPU_KMALLOC_V2; @@ -816,7 +817,7 @@ vm_init(void) if (INVALID_MEMBER(page_first_page)) ANON_MEMBER_OFFSET_INIT(page_first_page, "page", "first_page"); - } else if (MEMBER_EXISTS("kmem_cache", "cpu_slab") && + } else if ((MEMBER_EXISTS("kmem_cache", "cpu_slab") || MEMBER_EXISTS("kmem_cache", "cpu_sheaves")) && STRUCT_EXISTS("kmem_cache_node")) { vt->flags |= KMALLOC_SLUB; @@ -5270,6 +5271,9 @@ cmd_kmem(void) if (sflag || Sflag || rflag || !(vt->flags & KMEM_CACHE_INIT)) kmem_cache_init(); + if (Sflag && !MEMBER_EXISTS("kmem_cache", "cpu_slab")) + error(FATAL, "-S not supported for this kernel\n"); + while (args[optind]) { if (hexadecimal(args[optind], 0)) { value[spec_addr++] = @@ -20401,7 +20405,6 @@ get_cpu_slab_ptr(struct meminfo *si, int cpu, ulong *cpu_freelist) default: cpu_slab_ptr = 0; - error(FATAL, "cannot determine location of kmem_cache.cpu_slab page\n"); } return cpu_slab_ptr; -- 2.52.0